Model kingdom scale and a linked settlement using Dungeon Master's Guide community wealth, racial mix, power centers, businesses, and NPC class levels. Figures update as you edit inputs; use a seed to reroll random tables.
The Dungeon Master's Guide lists community sizes from thorps through metropolises, each with a maximum item value (gp limit) and modifiers for power centers and NPC levels. This calculator applies those rows to your town population.
Kingdom population is area in square miles times people per square mile (density). Settlement sizes, cultivated land, and castles follow the demographic tables in the DMG community creation guidelines.
The seed sets initial kingdom area and age, kingdom settlement rolls, and the random power centers, business counts, and class level dice. Reroll changes the town random tables while keeping the same seed until you choose a new one.